TIFFMEDIAN(1) USER COMMANDS TIFFMEDIAN(1)
NAME
tiffmedian - apply the median cut algorithm to data in a
TIFF file
SYNOPSIS
tiffmedian [ options ] input.tif output.tif
DESCRIPTION
tiffmedian applys the median cut algorithm to an RGB image
in input.tif to generate a palette image that is written to
output.tif. The generated colormap has, by default, 256
entries. The image data is quantized by mapping each pixel
to the closest color values in the colormap.
OPTIONS
-c Specify the compression to use for data written to the
output file: none for no compression, packbits for
PackBits compression, lzw for Lempel-Ziv & Welch
compression, By default tiffmedian will compress data
according to the value of the Compression tag found in
the source file.
LZW compression can be specified together with a pred-
ictor value. A predictor value of 2 causes each scan-
line of the output image to undergo horizontal dif-
ferencing before it is encoded; a value of 1 forces
each scanline to be encoded without differencing.
LZW-specific options are specified by appending a
``:''-separated list to the ``lzw'' option; e.g. -c
lzw:2 for LZW compression with horizontal differencing.
-C Specify the number of entries to use in the generated
colormap. By default all 256 entries/colors are used.
-f Apply Floyd-Steinberg dithering before selecting a
colormap entry.
-r Specify the number of rows (scanlines) in each strip of
data written to the output file. By default, tiff-
median attempts to set the rows/strip that no more than
8 kilobytes of data appear in a strip.
NOTES
This program is derived from Paul Heckbert's median program.
SEE ALSO
pal2rgb(1), tiffinfo(1), tiffcp(1), tiffcmp(1), libtiff(3)
"Color Image Quantization for Frame Buffer Display", Paul
Heckbert, SIGGRAPH proceedings, 1982, pp. 297-307.
Sun Release 4.1 Last change: September 26, 1994 1